This invention relates to a control system for controlling the flow of cooling and lube fluid through a torque-transmitting clutch.
In clutches, such as the traction or power-take-off (PTO) clutch on an agricultural vehicle, the clutch plates and discs are frictionally engaged. This friction generates heat and excessive heat can cause premature clutch wear and failure. For this reason, current production tractors, such as Deere 4-Wheel Drive Tractor Models 8450, 8650 and 8850, utilize hydraulically engaged wet clutches wherein cooled and filtered hydraulic oil is flowed through the clutch assembly. The cooling oil is flowed through these clutches continuously as long as they are engaged. However, energy is wasted when cooling oil flow is continued beyond the time when the excess heat has been removed from the clutch.
A system for providing intermittent lube flow is described in U.S. patent application Ser. No. 545,981, filed Oct. 27, 1983, now U.S. Pat. No. 4,540,078, (Attorney's File 12357) and assigned to the assignee of this application. However, this system in application Ser. No. 545,981, now U.S. Pat. No. 4,540,078, requires a complicated hydraulic circuit with many hydraulic valves and, therefore, would be expensive to produce.